<template>
  <view>
    <!-- 自定义搜索组件 -->
    <my-search @click='gotoSearch'></my-search>
    <view class="scroll-view-container">
      <!-- 左侧滚动区域 -->
      <scroll-view class="left-scroll-view" scroll-y="true" :style=" { height: wh + 'px' }">
        <block v-for='(item , i) in cateList' :key='i'>
          <view :class="['left-scroll-view-item', active === i ? 'active' : '']" @click='activeHandler(i)'>{{ item.cat_name }}</view>
        </block>
      </scroll-view>

      <!-- 右侧滚动区域 -->
      <scroll-view class="right-scroll-view" scroll-y="true" :style=" { height: wh + 'px' }" :scroll-top="scrollTop">
        <view class="cate-lv2" v-for="(item2, i2) in cateLevel2 " :key='i2'>
          <view class="cate-lv2-title">/ {{ item2.cat_name }} /</view>
          <!-- 动态渲染三级分类的列表数据 -->
          <view class="cate-lv3-list">
            <!-- 三级分类 Item 项 -->
            <view class="cate-lv3-item" v-for="(item3, i3) in item2.children" :key='i3' @click="goGoodsList(item3)">
              <image :src="item3.cat_icon"></image>
              <text>{{ item3.cat_name }}</text>
            </view>
          </view>
        </view>
      </scroll-view>
    </view>
  </view>
</template>

<script>
 import badgeMix from '@/mixins/tabbar-badge.js'
 
 export default {
   mixins: [badgeMix],
    data() {
      return {
        // 窗口的可用高度 = 屏幕高度 - navigationBar高度 - tabBar 高度
        wh: 0,
        cateList: [],
        active: 0,
        cateLevel2: [],
        // 滚动条距离顶部的距离
        scrollTop: 0
      }
    },
    onLoad() {
      // 获取当前系统的信息
      const sysInfo = uni.getSystemInfoSync()
      this.wh = sysInfo.windowHeight -50
      this.getCateList()
    },
    methods: {
      async getCateList() {
        const {
          data: res
        } = await uni.$http.get('/api/public/v1/categories')
        if (res.meta.status !== 200) return uni.$showMsg()
        this.cateList = res.message
        this.cateLevel2 = this.cateList[0].children
      },
      activeHandler(i) {
        this.active = i
        this.cateLevel2 = this.cateList[i].children
        this.scrollTop = this.scrollTop === 0 ? 1 : 0
      },
      goGoodsList(item) {
        uni.navigateTo({
          url: `/subpkg/goods_list/goods_list?cid=${item.cat_id}`
        })
      },
      gotoSearch() {
        uni.navigateTo({
          url: '/subpkg/search/search'
        })
      }
    }
  }
</script>

<style lang="scss">
  .scroll-view-container {
    display: flex;
    .left-scroll-view {
      width: 120px;
      .left-scroll-view-item {
        line-height: 60px;
        text-align: center;
        background-color: #F7F7F7;
        font-size: 12px;

        &.active {
          background-color: #fff;
          position: relative;

          // 渲染激活项左侧的红色指示边线(伪元素)
          &::before {
            content: '';
            display: block;
            width: 3px;
            height: 30px;
            background-color: #C00000;
            position: absolute;
            top: 50%;
            left: 0;
            transform: translateY(-50%);
          }
        }
      }
    }
    .cate-lv2-title {
      padding: 15px 0;
      font-size: 12px;
      font-weight: 700;
      text-align: center;
    }
  .cate-lv3-list {
    display: flex;
    flex-wrap: wrap;
    .cate-lv3-item {
      display: flex;
      flex-direction: column;
      width: 33.33%;
      align-items: center;
      margin-bottom: 10px;
      image {
        width: 60px;
        height: 60px;
      }
      text {
        font-size: 12px;
      }
    }
  }
  }
</style>
